The use of a motor power connection box of this type for a three-phase motor is well known. The electrical contacting means are in the form of wiring connections that are soldered or clamped to the motor connecting contacts and the power supply connectors to give the desired performance function.
EP 1 895 642 A2 also discloses a motor power connection box for a three-phase motor, which motor power connection box comprises a housing and a cover. An electronic circuit for electrically influencing the respective three-phase motor is integrated in the cover. In order to provide different performance functions, different covers are provided that provide different electronic functions, which covers can be fitted to the housing and can be replaced according to the desired application. The different covers use the same electrical or mechanical interface to the bottom portion, that is to say, to the housing, in order to communicate with the electrical systems accommodated in the housing.
It is an object of the invention to provide a motor power connection box and a three-phase motor of the above type that exhibit improved variability.
As regards the motor power connection box, this object is achieved by making it possible to fit the cover to the housing in different orientations, and by integrating the electrical contacting means in the cover in at least two defined contacting configurations providing at least two different performance functions, which are alternately assigned to different orientations of the cover such that one of the performance functions is set whenever the cover is fitted to the housing. Thus the at least two different contacting configurations in the cover comprise contact points that are oriented toward the housing and that come into electrical contact with the power supply connectors and the motor connecting contacts when the cover is fitted to the housing. Thus the contacting configurations in the cover form suitable bridges or some other types of electrical connection for the purpose of setting one or other of the at least two different performance functions whenever the cover is fitted to the housing. The contacting configurations provide the missing conductors in the said electrical circuits for achieving a defined performance function. Typical performance functions include the operation of the three-phase motor in a Y connection or in a delta connection. Very preferably, the three-phase motor is an asynchronous motor. Only one of the said connections is completed and thus only one performance function for controlling the three-phase motor is available whenever the cover is fitted to the housing. Depending on the orientation, that is to say, the position in which the cover is fitted relative to the housing, it is possible to accomplish one or other of said connections and performance functions. In particular, the solution of the invention makes it possible to operate the three-phase motor in a delta connection or a Y connection by simply repositioning the cover. According to the solution provided by the invention, the three-phase motor can be operated in at least two different performance variants without the use of additional components that would have to replace existing components. According to the invention, the electrical contacting means comprise plug contacts or surface contacts in order to establish an electrical connection to the electrical contact points disposed in the housing.
In one embodiment of the invention, there are provided mechanical coding means on the cover and on the housing in order to enable the cover to be fitted to the housing in a defined manner depending on the performance function to be set. In a further embodiment involving indicating means that can be detected visually, haptically, or acoustically and that makes it possible to detect the performance function set according to the selected orientation of the cover after the cover has been fitted to the housing, such indicating means being assigned to the cover and/or the housing. In a particularly preferred exemplary embodiment, symbols are provided at two opposing edge regions of the housing for the purpose of indicating the delta connection or Y connection. There is provided an opening in the cover that registers with one or other of the symbols when the cover is fitted to the housing such that the symbol can be perceived in the fitted state of the cover. The contacting configurations are assigned inside the cover such that the performance function of the Y connection is also set when the symbol denoting the Y connection can be detected after the cover has been fitted to the housing. In a different orientation of the cover, it is then possible to perceive the other symbol through said opening. In a preferred embodiment of the invention, the different contacting configurations are offset through 180° relative to each other so that repositioning of the cover by 180° results in one or the other performance variant being set. This embodiment is advantageous in the case of covers and housings having a square base. Also, designs of the housing and cover that are polygonal and mirror-symmetrical relative to a central axis enable the cover to be repositioned in different angular positions that are predefined by the number of corners. Finally, it is possible to provide a cover and a housing having circular contact surfaces that likewise enable the cover to be fitted and oriented in different positions.
In a further embodiment of the invention, additional electric or electronic functional elements that are assigned to the respective performance functions are integrated in the cover. These electric or electronic functional elements can supplement the performance functions or generate additional functions. A particularly advantageous embodiment is intended for the suppression of interference. Advantageously, at least one capacitor can be used as an electric functional element for this purpose.
In a further embodiment of the invention, the cover is in the form of a single-part or multi-part component. Even when the cover is a multi-part component, it will form a component that can be handled as one piece when in its mounted functional position.
In a further embodiment of the invention, the cover can be removably or irremovably mounted on the housing. The possibility of removably mounting the cover on the housing is advantageous, since it is then possible to alter the performance characteristics or the performance function of the three-phase motor at a later point in time, according to requirements, by simply removing and repositioning the cover.
In a further embodiment of the invention, the cover is made of a plurality of cover layers which are superposed and capable of being joined together permanently and which comprise different contacting configurations and/or electric or electronic functional elements. A multilayered design of the cover makes it possible to achieve different function levels for electrical or electronic functions. The common feature of all the variants is that the cover can be handled as a single-part component following the assembly of the different cover layers and can be fitted to the housing in different orientations, as a result of which different connections of power supply connectors to motor connecting contacts can be achieved, depending on the orientation of the cover relative to the housing.
In an embodiment of the three-phase motor that is provided with a motor power connection box of such type, the motor power connection box is mounted on the motor housing by means of an adapter plate. As a result, it is always possible to attach the motor power connection box to the mounting point on the motor housing, irrespective of the dimensions of the motor power connection box.